Abstract

Objective

To compare the incidence and risk factors for gestational diabetes mellitus (GDM) between women with twin and singleton pregnancies.

Methods

Retrospective study of all women who had a twin or singleton birth in Ontario (2012–2016). Risk ratios (RR) and 95% CIs for GDM (stratified by type of treatment) were adjusted for relevant confounding variables. Multivariable Poisson regression analysis was used to identify risk factors for GDM in twin and singleton gestations.

Results

Of 270,843 women who met inclusion criteria, 266,942 (98.6%) and 3901 (1.4%) had a singleton and a twin pregnancy, respectively. Women with twins had a significantly higher risk for overall GDM (aRR = 1.13, 95% CI 1.01–1.28) and diet-treated GDM (aRR = 1.20, 95% CI 1.01–1.42) while the association with insulin-treated GDM was not significant (aRR = 1.07, 95% CI 0.89–1.28). Maternal age ≥ 35 years, non-Caucasian ethnicity and BMI > 30 kg/m2 were independent risk factors for GDM among women with twins and singletons, and the magnitude of the association of these factors with GDM was similar.

Conclusions

Women with twins are at increased risk of GDM, mainly due to a higher rate of diet-treated GDM. Despite higher baseline risk of GDM in women with twins, the effect of known risk factors for GDM is similar to that observed in singletons.

Keywords

Notes

Author contributions

LH researched data, wrote the manuscript and reviewed/edited the manuscript. HB reviewed the protocol involved in study design, reviewed and edited the manuscript. RO involved in the study design, protocol development, literature search. JGR reviewed and edited the manuscript. MG reviewed and edited the manuscript. SDM reviewed and edited the manuscript. BMD reviewed and edited the manuscript. RC data extraction, data analysis. IH involved in the conception of the study, writing of the protocol. HH data extraction, data analysis. JB assisted with the conception of the study, design, manuscript writing. NM researched data, wrote the manuscript and reviewed/edited the manuscript.

Funding

This study was funded by Canadian Institute of Health Research (CIHR) (Grant# 146442; Non-communicable Diseases in Obstetrics: Improving Quality of Care and Maternal-infant Outcomes Through an Obstetrical Research Network). Dr. Sarah D. McDonald is supported by a Tier II Canada Research Chair. Dr. Beth Murray-Davis is supported by a Hamilton Health Sciences Early Career Award. None of the funding agencies had any role in the idea, design, analyses, interpretation of data, writing of the manuscript or decision to submit the manuscript.